1. Field of the Invention
The present invention relates generally to ultrasound probes and, more particularly, to removable grips for ultrasound imaging probes.
2. Related Art
The use of ultrasound for medical imaging is well-known. Since its introduction, advances in technology and clinical practice have made ultrasound a leading medical diagnostic imaging modality. Ultrasound provides high-resolution real-time imaging without the use of ionizing radiation which is required for other techniques such as X-ray imaging. In addition, modern ultrasound equipment is relatively inexpensive and portable. This cost-effectiveness and portability has resulted in the widespread application of ultrasound imaging to observe a considerable range of physical conditions and to identify many types of disorders. For example, ultrasound imaging is commonly used in such clinical applications as obstetrics and gynecology, general abdominal imaging, vascular imaging and cardiology. This latter application, which is of significance in the present application, is referred to as echocardiography.
Non-invasive echocardiography is performed generally using a transthoracic ultrasound imaging probe. Conventional transthoracic ultrasound imaging probes are generally elongated devices having an ultrasound transducer located on the distal end of the device body. Ultrasound probes are generally constructed of a hard plastic casing to facilitate cleaning. Typically, the probe is maneuvered so that the transducer is positioned adjacent to an external location on the body where acoustic imaging is facilitated by the underlying tissue. In cardiac imaging, these locations, referred to as imaging windows, are typically in the vicinity of the rib cage.
There are four primary echocardiographic imaging windows: the suprasternal, subcostal, parasternal and apical windows. The appropriateness of each imaging window depends upon the structures, functions and conditions to be diagnosed as well as the type and size of the patient. Each imaging window provides an opportunity to image a specific portion or characteristic of the cardiac structures and/or functions depending on the portion of the heart which is nearest the selected imaging window, the angle of the probe at that window, and the intervening structures which may interfere with imaging the desired cardiac structures. In addition, the utility of certain windows is limited by the size and condition of the patient. Accordingly, specific windows are used to diagnose specific imaging conditions and disorders of specific patients.
When performing transthoracic echocardiographic procedures, the patient is generally lying horizontally on his or her left side. While the patient lies still in an appropriate position, the sonographer applies the transducer to a predetermined imaging window on the patient""s body. The transducer must be positioned at the correct location and in the correct orientation at the selected imaging window to successfully transmit the ultrasound signals at the proper angle so as to obtain clear and accurate cardiac images.
To place the probe in the proper position, the sonographer must maintain complete control over the probe throughout the echocardiograph procedure. This often requires the sonographer to apply a significant gripping force to the probe casing. Two techniques are commonly used. Left-handed scanning calls for holding the ultrasound probe with the left hand while manipulating the ultrasound imaging system controls with the right hand. Conversely, right-handed scanning calls for using the right hand to control the ultrasound probe while manipulating the imaging system with the left hand. Typically, a right-handed sonographer is positioned behind the horizontally-positioned patient. The sonographer must reach completely around the right side of the patient to properly position the ultrasound probe at one of the ultrasound imaging windows. The gripping force that must be applied by the sonographer to push and hold the probe in the proper location and orientation is significant in such an awkward position. In other situations, the sonographer may have to work in environments even more awkward, such as operating rooms, intensive care units, etc., as well as with patients that have difficulty remaining still, such as children and injured patients. It is not uncommon for the sonographer to repeat many procedures to ensure that the obtained images are accurate representations of the cardiac condition and not artifacts due to improper placement or orientation of the probe.
In addition, a large percentage of patients on which echocardiography is performed are obese. With these patients, the sonographer must apply a significant axial force to the probe to compress and displace layers of fat. Furthermore, the use of coupling gel to obtain a clearer image interferes with the sonographer""s capability to securely hold and control the ultrasound probe when the coupling gel migrates from the transducer onto the gripping surfaces of the probe casing.
Conventional probes generally have surface features to enable the sonographer to establish the proper orientation of the probe. For example, some ultrasound probes have curves, scallops or ridges, while other probes have a localized feature such as a line, rib, flute, button or some other feature on one side of the transducer. Although such orientation-related features of conventional ultrasound probes may provide some incidental assistance to the sonographer to maintain control over the probe, these features provide insignificant and insufficient assistance, ancillary to the purpose of establishing proper orientation of the probe.
What is needed, therefore, is a means for assisting a sonographer""s control of an ultrasound probe in various imaging scenarios, including different relative positions of the sonographer and the patient, varying patient conditions, and the presence or absence of coupling gel. Also, a range of gripping styles and hand sizes should be accommodated. The probe should be comfortable to hold and easily controllable with minimal gripping force to reduce fatigue and the occurrence of occupational injuries.
The present invention is an apparatus and a method related to a removable grip for an ultrasound probe. The grip is a hand-held device that, when located at a predetermined operative position on the probe, provides an exterior shape and size optimal for manually grasping during a desired application. In one aspect, the grip has an attachment feature that enables the grip to be detachably secured to the probe casing at the operative position such that manual forces applied to the grip to position the probe against a patient do not cause the grip to detach from the probe. The probe is generally an elongated instrument having proximal and distal ends and an external casing that is grasped by a sonographer. An ultrasound transducer is generally disposed at the distal end and a cord for transferring data and power typically extends from the proximal end of the probe.
In one aspect of the invention, a hand-held grip adapted to removably surround a substantial portion of an ultrasound probe is disclosed. The grip includes proximal and distal ends and a channel for receiving the cord. The channel is defined by opposing edges of the grip that longitudinally extend between the proximal and distal ends. The channel extends through the grip from an exterior surface to an interior surface of the grip so as to define a C-shaped cross-section of the grip.
In one embodiment, the channel has a width larger than a diameter of the cord, enabling the cord to pass freely through the channel. In another embodiment, the grip is flexible and the grip has an unbiased position in which the width of the channel is smaller than the diameter of the cord and a biased position in which the width of the channel is larger than the diameter of the cord. In this embodiment, a force must be applied to cause the cord to travel through the channel.
The attachment feature may take on any number of configurations. In addition, the probe may include one or more features on the probe casing that may be utilized in embodiments of the attachment feature to facilitate secure, yet detachable attachment of the grip. Thus, as used herein, the term xe2x80x9cattachment featurexe2x80x9d broadly covers any feature, configuration, or other aspect of the grip that facilitates a secure, yet detachable, attachment of the grip to the probe when the grip is located in the operative position on the probe. For example, in one embodiment, the probe is contoured so that it is narrower at its proximal and distal ends and wider in a mid-region between the proximal and distal ends. Here, the grip includes a tapered region on the interior surface. The tapered region tapers from a wider cross-sectional region toward the proximal end of the grip to a narrower cross-sectional region toward the distal end of the grip. The narrower cross-sectional region of the grip has an unbiased position that interoperates with the mid-region of the probe to prevent the grip from moving toward the proximal end of the probe.
In another embodiment, the exterior casing includes a raised region having a predetermined shape that provides an abutment surface substantially orthogonal to the surface of the exterior casing and the longitudinal axis of the probe. One or both of the opposing edges that form the grip channel have formed therein a recess configured to receive the raised region and to contact the abutment surface. As the grip is translated over the exterior casing, the grip is placed in an unbiased state as the raised region travels through the grip channel. When the recess in the one or both opposing edges receives the raised region, the grip attains a less-biased or unbiased state, resulting in the grip being detachably secured around a substantial portion of the probe.
The grip may also be detachably secured to the probe in a configuration in which the casing has at least one protrusion, and the attachment feature includes at least one corresponding indentation that is adapted to interlock with the protrusion of the casing when the grip is located in its operative position on the probe. Alternatively or additionally, the grip may have at least one protrusion and the casing at least one interlocking indentation. The protrusion of the grip is adapted to interlock with the indentation of the casing to detachably secure the grip to the probe.
In yet another embodiment, screw threads are formed on the external casing of the probe. In this embodiment, the attachment feature includes screw threads formed on the interior surface of the grip constructed and arranged to threadedly interoperate with the screw threads formed on the casing. In one particular embodiment, the grip includes a notch in the interior surface to align the grip with a detent on the probe thereby preventing the grip from rotating relative to the probe.
In one particular embodiment, interlocking mechanisms are disposed on the opposing edges of the grip that form the channel. The interlocking mechanisms are adapted to interlock with each other to enable the grip to be detachably secured to the probe.
In another aspect, the grip is not detachably secured to the probe. Rather, it is held in its operational position around the probe by manually applied axial forces toward the distal end of the probe. In one particular embodiment, the probe is contoured to have a cross-section at the proximal that is less than a cross-section at the distal end, with the external casing widening at a substantially constant rate between the proximal and distal ends. To interoperate with such an external casing, an interior surface of the grip is contoured to have a cross-section at the proximal that is less than a cross-section at the distal end, with the interior surface widening at a substantially constant rate between the proximal and distal ends of the grip such that the tapered interior surface contacts the exterior casing of the probe when the grip is in its operational position around the probe.
In many of the above or other configurations, the probe is nonaxisymmetric and the interior surface of the grip is also nonaxisymmetric to prevent the grip from rotating relative to the probe. The relative position of the grip with respect to the probe may be maintained by abutting surfaces. The probe may have an abutting surface and the interior surface of the grip may have a corresponding abutting surface. Contact of the abutting surfaces of the grip and probe prevents axial motion of the grip toward the distal end of the probe.
In another aspect of the invention a method for removably surrounding a unitary, C-shaped, hand-held grip around a substantial portion of an ultrasound probe is disclosed. The grip comprises proximal and distal ends and a channel defined by opposing edges of the grip that longitudinally extend between the proximal and distal ends. The channel extends through the grip, from an exterior surface to an interior surface of the grip. The probe is constructed and arranged substantially the same as described above. The method comprises the steps of removably receiving the cord through a channel extending along the grip and reversibly translating the grip from a location in which the cord is positioned with the grip to a location in which the grip surrounds the substantial portion of the probe.
Advantageously, the grip of the present invention, being larger than the probe and having some or all of the attributes mentioned above, enables an administering sonographer to maintain control over the ultrasound probe during transthoracic and other ultrasound imaging procedures while applying minimal gripping force. As a result, the sonographer is required to use less gripping force throughout the procedure, preventing fatigue and enabling the sonographer to perform ultrasound imaging procedures for longer periods of time without loss of control. Importantly, the grip enables the sonographer to efficiently obtain accurate ultrasound images from desired ultrasound viewing windows regardless of the position of the patient, the location of the sonographer relative to the patient, and whether the sonographer uses right- or left-handed techniques.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate like or functionally similar elements.